The inner solar system is overrated.
Neptune’s moon Triton is erupting, and scientists wonder whether it holds an internal ocean. Triton also orbits Neptune in the opposite orbit as the planet’s other moons, which means it could be a captured object from the Kuiper Belt.
4. Their compositions can help us understand how the solar system formed.
Some scientists think the Ice Giants formed much closer to the Sun and then moved outwards — but we won’t be able to confirm or refute this hypothesis until we can study Uranus and Neptune up close.